No more paper copyright registrations for groups of photographs
Starting February 20, 2018, the US. Copyright Office is changing the rules for registering groups of photographs. See 83 Fed. Reg. 2542 (Jan 18, 2018).
1. The US. Copyright Office no longer will accept paper copyright registrations for groups of photographs.
2. Instead, you can register unpublished or published groups of photographs (up to 750 photographs per claim) through a new online application.
3. You can submit an electronic deposit copy of each photograph (JPEG, GIF, TIFF), or send a physical media to the Copyright Office. In addition to the electronic deposit copy, you must submit a numbered list (XLS, PDF) containing the title and file name for each photograph in the group.
Image and licensing terms available here.